Assessment And Treatment Of Motor Vehicle
Accidents

An Overview

Motor vehicle accident injuries are as a direct result of the force of
the impact and the biomechanics of injury. Most motor vehicle
accidents are the typical hyperextension flexion injuries, or more
commonly known as "whiplash" injuries.

Motor vehicle accident injuries are a challenge to most physicians as
each mechanism of injury is slightly different. Knowledge of
musculoskeletal anatomy makes for a more precise diagnosis.

Most injuries are termed soft tissue injuries or musculoskeletal joint
injuries. These injuries occur from a front-end impact of
flexion/extension, mechanism, a rear-ended impact of
hyperextension/flexion mechanism, or a side impact of lateral flexion
mechanism. However, if a person is not sitting straight and looking
straight ahead, then the mechanism of injury becomes more complex.

Car manufacturers have made significant modifications in motor vehicles
to improve safety. Prior to seatbelts, most injuries occurred where
the body was thrown forward into the dashboard and windshield as an
unrestrained passenger. With the introduction of a lap seatbelt, the
driver was more restrained; however, at the time of impact, his/her
body sustains a jackknife movement over his pelvis which was stabilized.

The spine, however, would absorb significant force that have resulted
in spinal fractures and disc herniations. Further safety included
modification a headrest be positioned at the level of the occiput, and a
shoulder harness being added.

These modifications helped prevent some of the higher cervical spinal
cord injuries as well as allowed the torso to absorb most of the impact,
by limiting the forward motion of the occupant. Recent,
modifications included mandatory airbag systems safety, side impact
airbags and reinforced side beams have promoted a safer compartment within
the motor vehicle accident.

With the introduction of the airbag, there have been new types of
injuries, but non life threatening. With the deployment of the
airbag, the release of the powdery substance has caused eye injuries as
well as skin abrasions. The airbag deployment can also cause upper
extremity, chest and shoulder trauma from the force of the body's forward
acceleration against the deployment of the airbag.

In the 1980's and 1990's, motor vehicle accident injuries were studied
utilizing animals, volunteers and and anthropomorphic dummies. Prior
to a significant protest of animal rights, animals were anesthetized and
strapped into seats, as they were accelerated in elevator shafts
simulating front and rear-ended motor vehicle accidents. The monkeys
were used as the animal models. The animals were then dissected and
were found to have multiple microbleedings in the dermal layer of the
upper torso, shoulder and pelvic regions.

In the 1980's, English researchers did postmortem autopsies on humans
who died in motor vehicle accidents and found significant intrapelvic
sacroiliac bleeding that previously was under recognized among clinicians.

The recent modeling of anthropomorphic dummies using sophisticated
computerized sensors does not truly simulate the human's reflexive
protective mechanisms a person has when faced with imminent trauma.

Rear-ended impacts usually result in a more severe and disabling injury
than front end or side collisions of the same force. Anatomically,
humans have a built in restraint system in the neck, as the chin is
limited in its forward flexion by the sternum. However, this
anatomic restraint is lacking in the hyperextension movement.

Video analysis shows that in moderately high speed impacts, without a
headrest, the forward motion of our head is limited as the chin strikes
the sternum, whereas in hyperextension, it exceeds its functional range to
the point that the top of the head may actually approach touching the
upper mid back between the shoulder blades.

Side impact injuries have built in anatomical restraints being our
shoulders. As the side impact throws our neck sideways, our ear will
strike the shoulder as the maximal allowable range of motion.

Flexion/extension injury is often referred to as cervical strain,
whiplash injury or cervicalgia. This mechanism of injury results in
syndromes of pain due to straining of cervical muscles, spraining of
ligaments, trauma to the discs and traction of the exiting nerve roots.
The degree of damage to these structures varies depending on the degree of
the force of impact.

In the cerebral evaluation, one should assess for any loss of
consciousness. Brief unconsciousness occurs in approximately 10% of
the patients. Presentations include symptoms of confusion, mental
dullness or mild amnesia after the injury. Concussion-like symptoms
may present themselves with inability to recall events of the accident, as
well as complaints of headache, dizziness, nausea, vomiting or visual
changes.

The cervical evaluation should be thorough as cervical pain is the most
common early symptom. Assessment of range of motion should be done
as well as correlating lack of range of motion to specific strained
musculoskeletal structures.

Another frequent complaint is swallowing difficulty that lasts a few
days following the motor vehicle accident. With significant force, a
flexion/extension the anterior longitudinal ligament can be sprained
resulting in edema anterionly and creating mechanically induced swallowing
pain.

Patients who are examined minutes or hours immediately after a motor
vehicle accident usually show few clinical findings as they may lack the
soreness or muscle tightness and may have a relatively functional range of
motion.

Within a couple days, tightness and spasm with secondary edema develop,
limiting range of motion and continue to get progressively worse
over the next few days.

Patients with mild sprains usually improve within seven to ten days,
but symptoms may last for several weeks or months in more moderate or
severe injuries.

Prolonged muscle tightness and spasm leads to secondary deconditioning
that further prolongs the duration of symptoms.

Headaches are usually a source of referred pain from the cervical
structures. Occipital headaches with radiation bitemporally and then
into the eyes are not uncommon and are usually due to referred muscle pain
from the upper trapezial muscles.

Pain radiating from the neck into the shoulders and arms, is more
commonly a myofascial referred pain from the muscles themselves, but in
more severely injured individuals can be a manifestation of the irritation
of the nerve roots or brachial plexus.

Actual nerve deficit is rare. Non-neurogenic radiation of pain,
paresthesias and numbness usually results from trigger points of
musculoskeletal muscles and ligaments and usually does not follow a
typical nerve root or peripheral nerve distribution pattern.
Neurogenic pain in contrast is characterized by a clearly defined pattern
of sensory or motor distribution with changes in reflexes and can be
documented electromyographically with a nerve study of EMG and nerve
conduction study (NCS).

Following a motor vehicle accident neck
injury, the patient tends to hold the neck in a slightly forward position.
This position is probable helpful in reducing the pain, as it does not
depend on any muscle contraction. Unfortunately, it produces a
cumulative overstrain of the supporting posterior, musculoligamentous
structures.

To give an example, the typical head of the human
adult weighs approximately 10 to 12 pounds. Simplifying the model
position a ten pound bowling ball on a broomstick. Proper erect
position will correlate to a ten pound weight being balanced.
However, moving the bowling ball three inches in either direction will
create a force of 30 pounds needed to support on the broomstick, a factor
of three times the actual weight. Therefore, it is the goal of the
therapist and clinician to promote proper postures to help alleviate the
secondary strains from the malaligned spine.

In an abrupt stop,
the seatbelt on the left shoulder will force the torso and chest
backwards. Frequently, one can see bruising over the area of the
seatbelt with more moderate or severe impacts. The chest/thorax area
is susceptible to rib fractures and mild subluxations or dislocations when
being struck by an airbag or striking steering column. Clinical
symptoms of shortness of breath, pain with breathing, coughing or laying
down are symptomatic of a possible rib fracture or dislocation.

The position of the arms, hands and wrists at the time of impact will help
assess for possible injury. If the individual held their arm in a
fully extended position while firmly gripping the steering wheel, an
individual may develop secondary wrist trauma through the carpal area.
This wrist injury may predispose individuals to carpal tunnel
symptomatology or tendonitisis in the forearms.

Abdominal
injuries are quite uncommon. Should a patient be restrained at a
high impact, then injuries to the internal organs may result.
Hemorrhages of kidneys, liver and spleen have occurred with high impact
injuries of flexion/extension with an abrupt stop.

The second
most common site of injury is the low back, sacral, pelvic area. As
the body is restrained with the legs extended, the impact is absorbed
through the pelvic/sacral areas. Frequently, subluxation of the
sacroiliac joints occur which directly affect the L4, L5 and S1 vertebral
complexes. Impacts where the patient reports the actual driver's
seat breaking should direct the clinician to do a thorough examination of
the sacroiliac structures.

The lower extremities in full
extension either in the process of applying the clutch or trying to brake
with the leg extended may cause injuries such as ankle sprains, lateral
leg and thigh strains with secondary development of trochanteric bursitis.
In certain vehicles with more protruding dashboards, long legged
individuals sustain direct knee trauma across the patella/intrapatellar
area. Direct knee trauma most likely causes retinacular capsular
trauma and resulting knee pain. Actual meniscal or cruciate damage
is unlikely. Swelling is usually superficial rather than
intra-articular.

The TMJ/jaw area is frequently missed by
clinicians. The jaw is a joint that allows movement. In
flexion/extension injuries, the mandible moves forward and then back into
position. Frequently, this causes disruption of the temporomanibular
joint and disc leading to subluxation and secondary temporalis muscle
strain causing referred headache pain.

Following the motor
vehicle accident, the patient is assessed for injuries. At the scene
of the accident frequently, emergency services will evaluate the patient.
If there has been any loss of consciousness, significant neck and headache
pain, the patient may be stabilized on a cervical board and brought to the
emergency room for a more detailed evaluation. If the emergency room
evaluation findings are primarily musculoskeletal soft tissue, the patient
may be released with instruction to follow up with the primary physician.

If there is any loss of consciousness, the patient in the emergency room
will undergo a CT-scan of the head to rule out intracranial bleeding.
Spinal injuries or musculoskeletal injuries will be evaluated by plane
x-rays. However, if there is any concern about possible fractures, a
CT-scan may be performed. Intra-abdominal injuries can also be
assessed by plane x-ray but more specifically with a CT-scan.

In the emergency room, pain management is provided by intramuscular
injections of anti-inflammatories or pain pills, and the patient is
released with a small amount of Class III narcotic with the combination of
a muscle relaxant and anti-inflammatory. Medication prescriptions
provided are usually for 48-72 hour duration with the direction of
following with a primary physician for further care needs.

The
patient's treatment choices are varied; however, they should be
directed to some clinician who provides manual treatment.
Chiropractors can provide adjustments and as co-treatment incorporate
massage therapy and physical therapy within their practice.

Traction is occasionally utilized by
clinicians, chiropractors and osteopathic physicians to reduce the
intervertebral tightness along the spine.

Passive treatments,
which include modalities, are hot, cold and ice. The first 24 hours
should be reserved for icing to reduce the swelling and physical
compression to limit the secondary edema. Ice is also utilized after
manual therapy where tissue is actively worked on and can reaggravate the
developing edema. Other modalities used by therapists include
ultrasound, iontophoreses, electrical stimulation, laser as well as
recently cold light treatments.

With the awareness of holistic
medicine, patients may request alternative treatments in the form of
herbal or homeopathic medications, acupuncture, craniosacral, Pilates,
personal fitness training or Chinese medicine.

Should a patient
have any radiculopathy including pain, numbness, tingling or weakness in
the extremities, an MRI is indicated to rule out a disc lesion that could
impinge a nerve root. Nerve conduction study to assess any nerve
damage should only be done three weeks after the initial injury, as being
done too early may not have the objective findings in this test.

Thermography is debated for acceptance as a diagnostic tool.
Thermography is able to assess variations in body temperature as injured
myofascial structures with more edema, show slight increases in
temperature when compared to non-traumatized tissue.

Studies
show that symptoms of extremity radicular numbness or pain, sharp reversal
of cervical spine curve, prolonged spinal traction or prolonged wearing of
a cervical collar more than three months, are poor prognostic factors
following the motor vehicle accident.

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